Producing dual torque yarn



Jan. 24, 1961 M. H. coMER ETAL 2,963,909

PRonucINs DUAL ToRQUE YARN Devov TERRQLL and CHAQUE A. M 1:55.l

ATTORNEY@ Jan. 24, 1961 M. H. COMER Erm- PRoDucING DUAL TORQUE YARN 3 Sheets-Sheet 2 Filed May 29, 1956 TERRE and C-HARUE A. M LES,

Y O V E D INVENTOR S ATTORNEYS Jan- 24, 1961 M. H. COMER ETAL PRoDucngG DUAL ToRQUE YARN Filed May 29, 1956 3 Sheets-Sheet ///////.///dpl/ rates PiDBUClNG DUAL TORQUE YARN Filed May 29, 1956, Sel'. No. 588,069

2 Claims. (Cl. 57-157) This invention relates to the production of lively synthetic thermoplastic yarns such as nylon and the like and, more especially, to improvements in apparatus for and the method of imparting twist to the yarn.

In the knitting of highly stretchable hosiery and other stretchable fabrics made from synthetic yarn it is customary to knit spaced portions or courses from a lively yarn which has been twisted in one direction and to knit intervening portions or courses from a lively yarn which has been twisted in the opposite direction in order that the torque inuenced in the fabric by the yarns is equalized in opposite directions and to thereby prevent the resultant product from curling or twisting, i.e., so the resultant product will lie flat.

The present method of producing lively or torque synthetic yarns such as nylon and other thermoplastic yarns comprises generally the withdrawing of a single end of yarn from a pirn or yarn package through suitable guiding and tensioning means and then through a heating unit. From the heating unit the yarn passes through a constantly rotating hollow twister spindle of the false twist type which twists the yarn in one direction while it is passing through the heating unit. During the twisting of the yarn in the heating unit it is subjected to a temperature which is sufficient to set the twist in the yarn and to maintain the torque therein during any subsequent processes to which the yarn or any fabric produced therefrom may be subjected. From the twister spindle the yarn is guided to and wound upon a takeup bobbin and is untwisted between the twister spindle and the takeup bobbin. t

The use of two oppositely twisted yarns has many disadvantages including the requirement for two yarn feeds in knitting operations, excessive time and expense, etc. It is obvious that it would be highly desirable to produce a single end of yarn which is lively throughout its length, but which has a balanced torque, so as to obtain stretchability in the resulting product without the necessity of using oppositely twistedyarns. Various attempts have been made to produce a satisfactory yarn, which is lively throughout its length and which has alternate portions thereof twisted in opposite directions, with the use of present equipment. But such attempts have not been wholly satisfactory due to the fact that they necessitate the rotating of the twister spindle alternately in first one direction and then the other. Unless the direction of rotation of the spindle or other twister element can be changed substantially instantaneously, a lag or untwisted area will result between each adjacent pair of portions of twisted or lively yarn. This results in a yarn which is not lively throughout its length so that the resulting fabric is unirorm as to its stretchability and is blemished with streaks or shadow lines caused by ein;

Patented Jan. 24, igi.

particularly critical in the knitting operation. Attempts to use a reversible motor driving a belt which engaged and rotated the spindles failed due to the fact that it was necessary to momentarily stop the motor each time a change in the direction of movement of the belt was made which resulted in a momentary dwell in the rotation of the spindles between each change in the rotation thereof, which dwell produced a lag or untwisted section between each adjacent pair of twisted portions. Other attempts, while much more satisfactory, necessitated various extensive and expensive changes to existing equipment.

It is therefore an object of this invention to provide an improved method of and apparatus for producing twisted lively synthetic yarn, from individual ends of thermoplastic yarn, having alternate sections of opposite torque throughout the length thereof without any lag or untwisted portions between contiguous sections. In carrying out the process an end of yarn is constantly withdrawn from a pirn or yarn package and twisted and then untwisted by a false twist spindle and then wound onto a takeup bobbin. As the yarn is being withdrawn and twisted a setting heat is applied in advance of the twister spindle to alternate sections of predetermined length thereof which is sufiicient to heat set the sections to which the heat is applied. As the yarn is subsequently untwisted between the twister spindle and the takeup means, the unset portions of the yarn will be untwisted to substantially zero torque and the set portions of the yarn will be reverse twisted resulting in liveliness or torque in these sections. This produces a yarn having alternate heat set and twisted torque sections and unset and untwisted nontorque sections.

The yarn thus far produced is then continuously withdrawn from the takeup bobbin and again processed through the twisting apparatus turning in an opposite direction. As the yarn is being twisted in the opposite direction and then untwisted a setting temperature is continuously applied thereto which is suicient to set the twists or turns in the previously unset sections. This produces a monolament of lively yarn having alternate sections thereof of high torque in one direction with the contiguous intermediate sections of high torque in the opposite direction without any lag or untwisted portions between contiguous sections thereof.

In order to produce yarn in accordance with the aforesaid process, we employ standard yarn twisting equipment in which yarn is continuously withdrawn from a yarn package past a heating unit and through a false twisting spindle and then wound onto a takeup bobbin; and in conjunction with the aforesaid equipment we provide means by which alternate sections of the yarn being withdrawn and twisted are moved out of and into heat setting proximity with the heating unit whereby only alternate portions of the yarn are heat set. The strand of yarn thus produced, having only alternate sections thereof lively in the same direction, is again drawn through the twisting equipment and twisted in the reverse direction with a setting heat being applied throughout its entire length whereby the previousiy unset nontorque p alternate sections of the strand arerendered lively in an the untwisted `or lag areas in the yarn. `Such lag areas,

in tension throughout the length of the yarn, which is' opposite direction to the liveliness or torque of the sections twisted and heat set and untwisted during the first passage of the strand or filament through the twisting equipment. The setting temperature applied to the yarn must necessarily be suicient to maintain liveliness of the yarn during any further processes to which the yarn or fabric made therefrom may be subsequently subjected. But the temperature initially applied intermittently to the yarn to set the twists in alternate sections hereof must be somewhat greater, for instance, 25 F. to 30 F., than that subsequently applied continuously to the yarn to set the reverse twists in the previously unset sections to insure that the alternate sections initially twisted and heat set are not aifected.

The principal object ofthe invention having been stated other than more limited objects of the invention will' be apparent from the following specification and the accom-` panying drawings forming a part thereof in which- Figure l is a somewhat schematic front elevation, partially broken' away, of a conventional twisting machine having the presently preferred embodiment of the mech.- anism of our invention for controlling the application of setting heat to an end of yarn being twisted, incorporated therein;

Figure 2 is a somewhat schematic enlarged transverse vertical sectional View taken substantially on the line 2 2 in Figure l;

Figure 2-A is lan enlarged vertical sectional view through the upper portion of the twisting spindle taken substantially along line Z-A-Z-A in Figure 2;

Figure 3 is a somewhat schematic horizontal sectional view, on the same scale as Figure 2, and taken substantially on the line 3 3 of Figure 2; and

Figure 4 is a somewhat schematic vertical sectional view taken substantially on the line 4-4 of Figure 3.

There are many different types of twister machines with which the ymechanism of our invention may be used, accordingly, in the drawings only such parts of a conventional twisting machine are shown as are necessary to illustrate the application thereto of our new apparatus for carrying out our new and improved method of producing twisted synthetic yarn. Referring now to the drawings by reference characters, the numeral 1 indicates generally :a conventional twisting machine having the longitudinally spaced vertical head and foot end frame members 2 and 3, and a horizontal shelf 4 having the downwardly extending side flanges 5 which is secured to and extends between the frame members 2 and 3 intermediate the upper and lower ends thereof. A suitable Creel 6, on which are mounted a plurality of pirns or yarn packages 7 from each of which is drawn a strand of yarn Y during operation, is secured to and extends between the end members 2 and 3 adjacent the lower ends thereof.

Yarn is withdrawn at each side of the machine l from the yarn packages 7 up through pigtail guides 8 and conventional guiding and tensioning means 9 by standard conventional withdrawing mechanisms lil which together with the guiding and tensioning means 9 are mounted upon plates 11 which are secured to and between the end frames 2 and 3. From the tensioning and withdrawing mechanisms 9 and 10 the strands Y of yarn are pulled up past heating units 12 and through twisting spindles 13 by driven takeup bobbins 14 upon which the strands of yarn are wound after passing the heaters 12 and twisting spindles 13'. The takeup bobbins 14 rest upon and are driven by'takeup rolls 15 which are mounted upon rotatable shafts 16, and over which the strands of yarn pass as they are wound onto the takeup bobbins 14. The strands of yarn are guided onto the bobbins 14 for even distribution thereon, by traversing thread guides 17 carried by traverse bars 18 which are reciprocated back and forth by conventional traverse gear and cam mechanism generally indicated by the numeral 19.

The heating units 12 which are of standard conventional construction are secured in position between the end frames 2 and 3 immediately below the twisting spindles 13 by brackets 20. Each heating unit 12 comprises a heating element 21 having vertical grooves 22, in the outer face thereof, n which the strands of yarn are received as they are pulled upwardly past the heating units 12 and into the twisting spindles 13. The heating elements 21 are mounted in casings 23 having the removable covers 24 which are spaced from each other as indicated at 25 to provide for the reception of the strands of yarn in the heating element grooves 22. Suitable heat insulating material 26 is provided for the heating elements 21 Within the casings 23 and covers 24.

The twisting spindles 13 are also of standard conventional construction and eaoh comprises a non-rotatable casing 30 which is suitably secured to a side flange 5 of the table 4. A tubular spindle whorl 31 is rotatably mounted in the casing 30. A conventional twisting head 32, shown in the form of a roller (Figure 2-A), is mounted in the upper end of the whorl 31 for rotation in lateral relation to the whorl 31. It will be observed that yarn between the twisting head 32 and the withdrawing mechanism 10 will be twisted in one direction and will be twisted in the opposite direction between the twisting head 32 and the takeup bobbin 14 in a manner well known in the art. The spindle whorls 31 are all rotated in unison by an endless belt 33 which is mounted upon the grooved pulleys 34 and 35 and is driven by a motor 36 through the pulley 35 which is secured to the upper end of the armature shaft 37 of the motor 36. The motor 36 is secured to the underside of a carriage 38 having rollers 39 secured to the carriage by which the carriage 38 is reciprocally mounted upon suitable tracks (not shown) carried by the opposed faces of a pair of spaced brackets 40 which are secured to and between the head end frame member 3 and a suitable outboard frame member 41. A suitable tensioning means is provided by which tension is applied to the belt 33 and maintained constant at all times. This tensioning means comprises a rack 42 which is secured to the carriage 38 and meshes with a gear 43 mounted on a shaft 44. The gear 43 also meshes with a much smaller gear 4S secured to the shaft 46 which also has a drum 47 secured thereto. A cable 48 which is secured to the drum 47 and extends downwardly therefrom has a Weight W secured to the :lower end thereof. Weight W, through the cable 48, constantly biases the drum 47 in a clockwise direction which in turn through the gears 43 and 45 and the rack 42 constantly urges the carriage 38 and consequently the pulley 35 outwardly from the head end frame 2 and thereby maintains a constant tension on the belt 33. The belt 33 extends through cut out sections 50 in the spindle casing 30 and is maintained in contact with the rotatable spindle whorls 31 by idler rolls 51 which are suitably mounted on the shelf 4. It will therefore be apparent that the spindle whorls 31 will all be rotated in unison in the same direction by the belt 33 as it is driven by the motor 36 through the pulley 35. Suitable throwout mechanism 52 is provided for each of the spindles 13 by which they may be thrown into and out of engagement with the belt 33 as desired.

The yarn withdrawing mechanisms 10, the takeup rolls 15, and the traversing gear and cam mechanisms 19 for the thread guides 17 are all driven from the pulley 34 through suitable gearing and connecting chains all of which is schematically shown in dotted lines in Figure l and are generally indicated by the numeral 53.

The twisting machine thus far described is of standard well known construction such as is extensively used at the present time to continuously twist and heat set and untwist synthetic thermoplastic yarn. In twisting machines of this character thek strands of yarn Y are twisted by the twisting spindles 13 as the strands are Ibeing drawn past the heating units 12. The actual twisting of the yarn occurs while the strands are disposed in the grooves 22 where they are subjected to the setting temperature of the heating elements 21.

.In producing yarn having alternate sections thereof twisted and heat set in opposite directions, according to our improved process, we incorporate means in a ma# chine of the aforesaid character by which alternate sections of strands of yarn being twisted are moved out of the grooves 22 to such an extent that they are not subjected to the setting temperature of the heating elements 21. This will produce a strand of yarn which is oon.-

tinuously twisted throughout its length in the samev direc- A tion but in which only alternate sections thereof of preaccesos determined length are heat set. As the yarn is then untwis-ted the twist torque will be removed from the intervening unset sections and twist torque in the opposite direction imparted to the set alternate sections. Then by again continuously drawing the yarn thus processed through the twisting machine and twisting it throughout its length a direction opposite to the initial twisting while continuously subjecting it to a setting temperature lower than that used in the rst step, and then untwisting the yarn, we produce a strand of yarn having alternate sections thereof of predetermined length provided with twist torques of opposite directions.

As a specific example of the process and a further illustration thereof, a single end of denier monolament nylon yarn is first processed through the twisting apparatus operating at a speed and direction to impart turns of S-twist to the yarn between the twisting head and the withdrawing mechanism. Obviously, the yarn is untwisted a like amount between the twisting head and the takeup mechanism. The yarn is permitted to contact the heating element at alternate sections of 50 inches in length and is moved out of contact with the heating element for intervening sections of 50 inches of length. Thus, 30 turns of S-twist is imparted to a rst section of the yarn, heat set and then this section of the yarn is untwisted for 30 turns, resulting in zero twist in this 50 inch section. The adjacent intervening section will have 30 turns of S-twist imparted thereto and not set and then untwisted a like amount resulting in zero turns in this section of the yarn.

The yarn is then run through the twisting apparatus again. The apparatus is run to impart 30 turns of Z- twist to the yarn between the twisting head and the withdrawing mechanism and to untwist the yarn a like amount between the twisting head and the takeup mechanism. The yarn in the subsequent process is subjected to heat setting throughout its entire length at a temperature less than that used in the rst step. Thus, the 50 inch section of yarn which previously had been twisted 30 turns per inch S, heat set, and untwisted 30 turns per inch Z, will have an additional 30 turns of Z-twist imparted thereto, making a total twist torque equivalent to 30 turns. The yarn is set at a lower temperature than its original setting and then untwisted 30 turns leaving a net twist torque of 30 turns in this section of the yarn. The section of yarn which previously had been twisted 30 turns per inch S without heat setting and untwisted thirty turns per inch Z and which therefore had substantially no twist or torque therein will have 30 turns of Z-twist imparted thereto and set therein and will then be untwisted a like amount to impart 30 turns of S-twist to this section of the yarn. The resulting yarn will have alternate 5() inch sections of 30 turns of Z-twist torque and intervening 50 inch sections of 30 turns of S-twist torque without any lag therebetween.

Obviously, the process may be reversed and the same results obtained. For example, the yarn may rst be processed by twisting, setting and untwisting with the setting being continuous but at a low temperature. Then, the yarn is again twisted, set, and untwisted, the twist being opposite to that initially applied and the setting being intermittent and at a higher temperature than the initial set.

The mechanism of our invention by which alternate sections of predetermined length of strands Y of yarn being twisted are moved into and out of heat setting proximity with respect to the heating elements 21 will now be described. This mechanism comprises a pair of similar frames 55 and 56, one of which is disposed in operative relation to each of the heating units 12. Each of the frames 55 and 56 comprises two vertically spaced parallel bars 57 and 58 which are disposed above and below a heating unit 12 in position to engage the strands of yarn being drawn past the heating units 12 and through the twisting spindles 13 from the pirns or yarn packages 7 by the takeup rolls 15. The bars 57 and S8 are secured to and carried by a plurality of generally U-shaped connecting members 59 which are connected together by a rod 60 which is disposed behind a heating unit 12 parallel to the bars 57 and 58. Each of the connecting members 59 are secured to and carried by a pair of spaced parallel transversely extending slide bars 61 which are slidably mounted in bearing blocks 62, 63 and 64. The bearing block 62 is secured to the end frame 2 by bracketing means 65, and the block 63 is secured to the end frame 3 by bracketing means 66. The bearing block 64 is secured to a pair of rods 67, which extend downwardly from the shelf 4, by bracketing means 68. The frames 55 and 56 are yieldingly biased inwardly away from the heating units 12 by coiled springs 69 which are secured to and between the connecting members 59 and the blocks 62, 63 and 64. The connecting bars 60 carry a plurality of inwardly extending arms 70 having rollers 71 secured to the free ends thereof. The rollers 71 are held, by the springs 69, in engagement with similar cams 72 which are carried by a shaft 73 rotatably mounted in bearings 74 secured to and extending upwardly from the bracketing means 65, 66 and 68. The cams 72 are provided with high and low arcuate edges 75 and 76 respectively which are connected together by the inclined edges 77. The shaft 73 is rotated, and with it the cams 72, from one of the takeup roll shafts 16 through the sprockets 78 and 79 and the connecting chain 80. The rotation of the cams 72 will impart an inward and outward movement to the frames 55 and 56 with respect to the heating units 12 associated therewith. By reference to Figure 2 it will be seen that the frames 55 and 56 are moved back and forth in unison and that when one of the frames 55 or 56 is held in outward position by the high edges 75 of the cams '72 lthe other frame 55 or 56 will be held in inward position by the lower edges 76 of the cams 72 and the springs 69. It will also be seen that by reference to Figures 2 and 3 that during the time the frames 55 and 56 are maintained in their inward position the strands Y of yarn being twisted will be disposed in the grooves 22 in heat setting contact with the heating element 21; and that during the time the frames 55 and S6 are maintained in their outward positions the bars 57 and 58 will hold the strands Y of yarn being twisted away from the grooves 22 and out of heat setting proximity with respect to the heating elements 2i.

In practice, it has been found that adjacent portions of the yarn having` opposite twist torques may be from two inches to one hundred inches long, regardless of the denier of the yarn, although it is preferable that the recurring lengths or portions of the yarn having a twist torque in one direction are approximately' fty inc-hes long, since in knitting the usual stocking, each course requires approximately twelve and one-half inches of yarn and a fty inch length of yarn is, thus, equivalent to approximately four knit courses. In other words, in knitting a stocking in which each portion of the yarn is fifty inches long, spaced groups of four courses, with four intervening courses therebetween, would have a twist torque in one direction and the four intervening course, in each instance, would have a twist torque in the other direction. Of course, it is contemplated that the yarn 4may be unbalanced; i.e., portions or a portion of the yarn having a twist torque in one direction may be thirty inches long and the adjacent portions or portion of the yarn having a twist torque in the other direction may be sixty inches long, for example.

Present demand for lively yarns is predominantly for sheer or monolament yarns and this invention will have its primary use with such yarns. it is toy be understood that, however, it may be used equally as well with multifilament or thermoplastic yarns of any practical size or denier and which are capable of being heat set and twisted to produce lively or stretchable characteristics. For ex- Z ample, such yarns as ArneL a triacetate; Dacron, a polyester; or other thermoplastic yarns may be used.

In twisting monofilament yarn it is preferable that each heating unit 23 subjects the corresponding strand of yarn to a temperature of 450 F., although this temperature may vary from 300 F. to 500 F. just so long as the temperature exceeds any Subsequent temperatures to which the yarn or fabric produced therefrom may be subjected. While the heating unit is illustrated as a contact type heater, it is t be understood that there are other types of heating and setting units such as steam jackets and radiant heaters which may be used.

Yarns of all denier from seven denier to forty denier may be twisted from tive to seventy-five turns per inch although it is preferred that the number of turns of twist per inch imparted to the yarn be varied according to the denier of the yarn substantially as appears in the following table:

Preferred number of Denier of arn:

y turns per' 'inch lt is thus seen that we have provided an improved method of and means for producing single ends of yarn having contiguous oppositely twisted portions therein throughout the entire length thereof, which method is made possible by the provision of means by which only alternate sections of a lament of yarn being twisted are subjected to a setting temperature.

In the drawings and specification there has been set forth the presently preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation; and it is to be understood that we are not limited to the specic construction shown and described herein as various modifications may be made thereto within the spirit of the invention and the scope of the appended claims.

We claim:

1. The method of producing torque yarn having reverse twist torques in alternating sections thereof which cornprises continuously advancing an end of yarn from a yarn package past a heating element and through a rotating twisting spindle by which the said end of yarn is continuously twisted in one direction as it is being advanced from said package and continuously untwisted beyond said spindle, intermittently moving said end of yarn into and out of setting relation with said heating element as said end of yarn isY being advanced and twisted to thereby heat set the twists in alternate sections of said end of yarn, and then advancing the said end of yarn thus processed past a second heating element and through a second twisting spindle by which the said end of yarn is twisted in a direction opposite to the initial twist and continuously untwisted beyond the second spindle, and maintaining said end of yarn in setting relation with said second heating element while said end of yarn is being advanced and twisted to thereby set the previously unset sections thereof.

2. The method of producing torque yarn as defined in claim l in which the setting heat initially intermittently applied to said' end of yarn is of a higher temperature than the setting heat subsequently applied continuously to said end of yarn.

References Cited in the tile of this patent UNITED STATES PATENTS 2,751,747 Burleson June 26, 1956 2,761,272 Vandamme et al. Sept. 4, 1956 2,780,047 Vandamme et al. Feb. 5, 1957 2,837,889 Comer June 10, 1958 2,909,028 Comer et al. Oct. 20, 1959 uw ...nl w. 

